1. Field of the Invention
This invention relates generally to supports for parked trailers and more particularly to novel parking stand for the tongue of a parked trailer.
2. Prior Art
This invention is concerned with trailers, primarily recreational trailers, of the type having a frame with a front tongue which can be coupled to a towing vehicle for travel and must be supported in an elevated position when the trailer :s uncoupled from the vehicle and parked. At the front end of this tongue is a coupling part to be engaged with a mating coupling part on the rear of the towing vehicle for connecting the trailer to the vehicle. The coupling part on the towing vehicle is an upstanding coupling ball having a projecting shank which is rigidly secured to the rear of the vehicle. The trailer coupling part comprises a rigid housing containing a downwardly opening cavity for receiving the coupling ball on the towing vehicle thru the open underside of the cavity and locking device for releasibly locking the coupling ball in the cavity.
A variety of coupling ball locking devices have been devised for such trailer couplings. A common type of coupling ball locking device comprises a lock member pivotally mounted in the housing of the trailer coupling part within a wall opening of the housing cavity for movement between locking and unlocking positions. When in its locking position, the lock member and the wall of the cavity form a generally spherical socket which is sized to rotatably receive the coupling ball on the towing vehicle. This socket has a bottom opening somewhat larger in diameter than the shank of the coupling ball on the towing vehicle but substantially smaller in diameter than the coupling ball proper. The ball may thus be locked in the socket with the ball shank extending thru the bottom opening of the socket to couple the trailer to the vehicle. When in its unlocking position, the lock member is retracted from the coupling housing cavity to enlarge the bottom opening of the socket to a size substantially larger than the towing vehicle coupling ball proper to permit engagement and disengagement of the trailer coupling part with and from the ball. Operatively connected to the lock member are manually operable means, such as a cam or screw for moving the lock member between its locking and unlocking positions and releasibly securing the lock member in its locking position.
One of the problems associated with a trailer of the character described resides in the fact that its longitudinal weight distribution is such that the trailer tongue must be supported in an elevated position when the trailer is uncoupled from the towing vehicle and parked. A variety of trailer parking stands for this purpose have been devised. Examples of such parking stands and other related trailer devices are described in the following patents:
U.S. Pat. No. 3,238,678: describes a trailer anchor having a top coupling ball to engaged in the trailer tongue coupling socket and a lower end to be inserted into the ground to retain the anchor upright.
U.S. Pat. No. 3,779,579: describes a rotatably extendable and retractable parking wheel support permanently mounted on a trailer tongue.
U.S. Pat. No. 3,797,283: describes a removable trailer tongue parking stand having an upper coupling ball which is engaged in the trailer tongue coupling socket and a lower auger which is screwed into the ground to both retain the support upright and prevent theft of the trailer.
U.S. Pat. No. 3,857,575: describes a trailer tongue parking stand having an upper coupling ball which is engaged in the trailer tongue coupling socket and a lower end which is permanently telescopically installed in a buried tube to both retain the support upright and prevent theft of the trailer.
U.S. Pat. No. 3,989,276: describes a trailer support in the form of a retractable jack stand to be permanently mounted on the trailer.
U.S. Pat. No. 4,063,750: describes a combined tow bar and parking stand for a trailer.
U.S. Pat. No. 4,548,418: describes a trailer tongue parking stand having an upper coupling ball for engagement in the trailer tongue coupling socket and a broad base for resting on the ground in a manner which normally retains the support upright.
Other commercially available trailer tongue parking stands are known, such as those manufactured by W. W. Gringer Inc., which have a vertical guide to be permanently secured to the trailer tongue and containing a tubular support member with a lower castor wheel which is vertically adjustable in the guide.
The above and other existing trailer tongue parking stands have certain disadvantages which this invention overcomes. The commercially available parking stands referred to above, for example, are quite heavy, costly and include at least one part, such as a guide, which is permanently mounted on the trailer. As a consequence, use of a stand of this type on a different trailer requires removal of the permanent part(s) from one trailer and mounting of such part(s) on the other trailer
The above and other existing trailer tongue parking stands and related devices which have a coupling ball for engagement in a trailer tongue coupling socket are devoid of any part(s) which must be permanently mounted on the trailer and in this respect are an improvement over the stands which have such part(s). These coupling ball-type parking stands, however, suffer from other and perhaps more serious disadvantages. These disadvantages reside in or result from the lack of any means on the stands themselves and/or the trailer for securing the coupling balls of the stands against swivel movement in the trailer tongue coupling socket as is necessary for the stands to provide a stable trailer support.
Thus, the coupling ball on such a parking stand and a trailer tongue coupling socket in which the ball is engaged constitute a ball and socket coupling which normally permits substantial swivel movement of the ball in the socket and thereby substantial lateral angular movent of the stand relative to the trailer tongue. Unless this freedom of swivel and lateral movement is eliminated, of course, the parking stand will not provide a stable support for the trailer tongue, and any slight movement of the trailer will cause the stand to lean over and drop the tongue.
In the patents listed above, the ground is utilized, in effect, to prevent swivel movent of the coupling ball in the trailer tongue coupling socket and thereby secure the parking stand against lateral angular movement. This is accomplished by either placing the lower end of the stand in the ground, as in U.S. Pat. Nos. 3,238,678, 3,797,283, and 3,857,575 or by providing the stand with a broad base which rests on the ground surface to maintain the stand upright, as in U.S. Pat. No. 4,548,418.
None of the trailer parking stands described in the above patents which have a coupling ball for engagement in a trailer tongue coupling socket embody any mean acting between the stands and trailers themselves for securing the ball against swivel movement in the socket. This results in the existing parking stands of this type having the following distinct disadvantages. Such parking stands cannot be equipped with a castor wheel or the like to facilitate movement of the supported trailer from spot to another. Those stands which must be pushed into the ground cannot be used on paved, asphalt or other hard surfaces. Those stands which utilize a buried receptacle for receiving the lower end of the stand involve the time and cost of installing the receptacle and can be used only at receptacle locations. Some of the stands are difficult and time consuming to install.
Accordingly, there is a definite need for an improved trailer tongue parking stand of the type having a coupling ball for engagement in the coupling socket on the trailer tongue. This invention provides such an improved parking stand.